共查询到20条相似文献,搜索用时 109 毫秒
1.
根据大失谐条件下原子-腔场相互作用的特点,讨论了一个制备纠缠压缩态的方法,提出了一个利用两能级原子与腔场相互作用实现纠缠压缩态纠缠浓缩的方案。在这个方案中,两束具有相同振幅但有着 相位差的压缩光 和 构成的纠缠态光场被用来作为量子信道。通过利用两能级原子与腔场的相互作用以及两模正交态测量实现了这个纠缠浓缩的过程。结果表明:对于纠缠压缩态,无论其初始的纠缠是多么微弱,利用这种方法总有一定的几率可以从部分纠缠态中提取出最大纠缠态。 相似文献
2.
This paper proposes a scheme for entanglement swapping based on cavity
QED. The two atoms to be entanglement-swapped can be separated
over long distance. The scheme is a non-post-selection one with
the success probability of 1/2. 相似文献
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Si-Chen Li Bang-Ying Tang Han Zhou Hui-Cun Yu Bo Liu Wan-Rong Yu Bo Liu 《Entropy (Basel, Switzerland)》2022,24(10)
Quantum networks enable many applications beyond the reach of classical networks by supporting the establishment of long-distance entanglement connections, and are already stepped into the entanglement distribution network stage. The entanglement routing with active wavelength multiplexing schemes is urgently required for satisfying the dynamic connection demands of paired users in large-scale quantum networks. In this article, the entanglement distribution network is modeled into a directed graph, where the internal connection loss among all ports within a node is considered for each supported wavelength channel, which is quite different to classical network graphs. Afterwards, we propose a novel first request first service (FRFS) entanglement routing scheme, which performs the modified Dijkstra algorithm to find out the lowest loss path from the entangled photon source to each paired user in order. Evaluation results show that the proposed FRFS entanglement routing scheme can be applied to large-scale and dynamic topology quantum networks. 相似文献
6.
We present to use a full-resonant four-level atomic system to generate the steady-state entanglement. This scheme is based on the nondegenerate four-wave mixing process with the four fields being resonant with the corresponding bare atomic transitions, unlike the previous mixing schemes, where the entanglement is achieved under the condition of off-resonance. Another feature of such a mixing is that four fields are coupled to the different atomic transitions, respectively. By choosing the atoms appropriately, entanglement occurs between the fields with the large frequency difference. 相似文献
7.
ZHENG Shi-Biao 《理论物理通讯》2005,43(2):315-317
A robust scheme is proposed for producing maximally entangled states for many trapped ions in thermal motion. In the scheme the ions are simultaneously illuminated by two standing-wave laser fields. During the operation the phases of the lasers are inverted, which not only cancels the vibration-dependent parts in the evolution operator, but also suppresses direct off-resonant coupling of the internal states. Thus, our scheme allows the production of entanglement for hot trapped ions with laser fields of high intensity, which makes the entanglement speed extremely high. 相似文献
8.
We show a scheme to distribute the entanglement by using three-mode separable Gaussian state prepared with imperfect equipments.The scheme achieves the aim that the entanglement is distributed between two distant parties with only Gaussian operations and linear optics elements.Moreover,we analyse the logarithmic negativity of the entanglement shared between the two parties when the systems are imperfect and arrive at the conclusion that the logarithmic negativity is asymptotically stable with fluctuations within a certain space range. 相似文献
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Stationary entanglement in a four-mode optomechanical system,especially under room-temperature,is discussed.In this scheme,when the coupling strengths between the two target modes and the mechanical resonator are equal,the results cannot be explained by the Bogoliubov-mode-based scheme.This is related to the idea of quantummechanics-free subspace,which plays an important role when the thermal noise of the mechanical modes is considered.Significantly prominent steady-state entanglement can be available under room-temperature. 相似文献
11.
Kaige Wang Li-ping Deng Gui-fang Dang 《量子光学学报》2006,12(B08):76-76
Two schemes for unconditionally generating two-mode motional entanglement for two ions trapped in a cavity have been proposed. The first scheme is: the vibrational mode of the first ion is coupled to the cavity field via a linear-mixing interaction and the vibrational mode of the second ion is coupled to the cavity field via an effective parametric interaction respectively. The two ions can evolve into a steady-state two-mode entangled Gaussian state, which is a mixed state. The second scheme is. the two ions are trapped in a bimodal cavity, through choosing the frequency and intensity of the driven lasers, the two ions can evolve into a two-mode entangled state, which is a pure state. 相似文献
12.
We propose a scheme for transferring entanglement through two independent arrays of coupled resonator waveguides, where a three-level atom is embedded in each resonator. We investigate the entanglement dynamics of the transferred state. The influence of initial states and applied lasers on the entanglement sudden death phenomenon is also discussed. Furthermore, we study the dynamics of pairwise quantum correlations measured by the quantum discord. 相似文献
13.
A scheme for concentrating entanglement in two partially entangled Einstein-Podolsky-Rosen (EPR) pairs using repetitious resonant
interactions of the atoms with a single-mode cavity field is proposed. A maximally entangled EPR pair can be deterministically
extracted with the success probability of 1.0. In the scheme, the two logical states of a qubit are represented by the two
lowest levels of an atom while a higher-energy intermediate level is used to facilitate the realization of the unitary operations,
and all the operations required to realize deterministic entanglement concentration can be implemented in a reasonable amount
of time before decoherence sets in. The scheme might be experimentally realizable with presently available cavity QED techniques
and gives a realistic means to realize entanglement concentration deterministically. 相似文献
14.
Using a system of cavity quantum electrodynamics(QED) we present two schemes for multipartite entanglement generation. In the first scheme, a three-level atom is interacting with three cavities successively. In the second one, two three-level atoms are interacted with a coherent optical cavity. These protocols allow us to generate the six classes of tripartite entanglement(GHZ, W, A-B-C, AB-C, C-AB, and B-AC class states) by controling the interaction time between atoms and cavities. Moreover, they allow us to generate entanglement between the cavity fields degrees of freedom(from the first scheme), and a mixed entanglement between the cavity field degrees of freedom and the atomic degrees of freedom. 相似文献
15.
Based on two atoms and two cavities initially in two pairs of atom-photon nonmaximally entangled states, we propose a relatively simple scheme to create maximally entangled photon-photon and atom-photon states via entanglement swapping using techniques of cavity QED inspired by the scheme proposed in [Phys. Rev. A 71 (2005)044302] and [Phys. Rev. A 71 (2005) 034312]. Our scheme does not involve the measurement in Bell basis, we only require detecting the states of atoms. 相似文献
16.
A genuine multipartite entanglement measure based on the geometric method is investigated in this paper. This measure has desirable properties for quantifying the genuine multipartite entanglement. A lower bound of the genuine multipartite entanglement measure derived with the fidelity-based method is then presented. The advantages of the measure proposed here with other measures are also presented. At last, examples are presented to show that the genuine entanglement measure has distinct entanglement ordering from other measures. 相似文献
17.
Benni Reznik 《Foundations of Physics》2003,33(1):167-176
We explore the entanglement of the vacuum of a relativistic field by letting a pair of causally disconnected probes interact with the field. We find that, even when the probes are initially non-entangled, they can wind up to a final entangled state. This shows that entanglement persists between disconnected regions in the vacuum. However the probe entanglement, unlike correlations, vanishes once the regions become sufficiently separated. The relation between entropy, correlations and entanglement is discussed. 相似文献
18.
WU Zhen-Zhen FANG Mao-Fa JIANG Chun-Lei 《理论物理通讯》2006,46(3):553-555
Based on two atoms and two cavities initially in two pairs of atom-photon nonmaximally entangled states, we propose a relatively simple scheme to create maximally entangled photon-photon and atom-photon states via entanglement swapping using techniques of cavity QED inspired by the scheme proposed in [Phys. Rev. A 71 (2005) 044302] and [Phys. Rev. A 71 (2005) 034312]. Our scheme does not involve the measurement in Bell basis, we only require detecting the states of atoms. 相似文献
19.
ZHAN Zhi-Ming 《理论物理通讯》2007,47(4):722-724
In this paper, a scheme is proposed to create the entanglement of two superconducting quantum-interference devices (SQUIDs) and implement a two-quhit quantum phase gate between two SQUIDs in cavity. The scheme only requires resonant interactions. Thus the scheme is very simple and the quantum dynamics operation can he realized at a high speed, which is important in view of decoherence. 相似文献
20.
Entanglement swapping between atom and cavity and generation of entangled state of cavity fields 下载免费PDF全文
This paper proposes a scheme where entanglement swapping between atom and cavity can
be realized. \Lambda -type three-level atoms interacting resonantly with
cavity field are considered. By detecting atom and cavity field, it
realizes entanglement swapping between atom and cavity. It uses the technique
of entanglement swapping to generate an entangled state of two cavity fields
by measuring on atoms. It discusses the experimental feasibility of
the proposed scheme
and application of entangled state of cavity fields. 相似文献